Trace element analysis using hollow cathode discharge (HCD) tubes will be studied from the standpoint of hollow cathode atomic emission and hollow cathode ionization. For emission, the HCD will be applied to those elements difficult to determine by conventional methods, such as atomic absorption. For ionization, a hollow cathode ion source will be used to do survey analysis of metals and nonmetals. Development will be toward the application of both modes to the analysis of trace elements in biological materials. Interferences of matrix effects, particularly from biological media, will be determined. Recovery efficiencies under various experimental conditions will also be determined. Comparisons of analytical results, as well as overall utility and potential, will be made with the hollow cathode techniques versus atomic absorption and spark source mass spectrometry with the aim of showing the complementary nature of these methods.